Polyoxymethylene compositions, articles comprising these compositions, and processes of making the compositions, comprising: a) at least one polyoxymethylene polymer; b) about 0.1 to about 5 wt. % of poly alpha-1,3-glucan having a d90 particle size of 50 microns or less; c) optionally, at least one additive selected from the group consisting of nucleating agents, waxes, ultraviolet stabilizers, colorants, antioxidants, formaldehyde scavengers, lubricants, and mixtures of these; wherein an article molded from said polyoxymethylene composition exhibits a formaldehyde emission of 1 weight percent or less when measured according to TEF test method.

Polyoxymethylene compositions, articles comprising these compositions, and processes of making the compositions, comprising: a) at least one polyoxymethylene polymer; b) about 0.1 to about 5 wt. % of poly alpha-1,3-glucan having a d90 particle size of 50 microns or less; c) optionally, at least one additive selected from the group consisting of nucleating agents, waxes, ultraviolet stabilizers, colorants, antioxidants, formaldehyde scavengers, lubricants, and mixtures of these; wherein an article molded from said polyoxymethylene composition exhibits a formaldehyde emission of 1 weight percent or less when measured according to TEF test method.

A tribologically modified polyoxymethylene polymer composition is disclosed. The polyoxymethylene polymer composition is comprised of a polyoxymethylene polymer and at least one tribological modifier. The tribological modifier may comprise at least one tribological modifier comprising an ultra-high molecular weight silicone having a kinematic viscosity of greater than 100,000 mm.sup.2 s.sup.1. The composition may exhibit a dynamic coefficient of friction against a counter-material of from about 0.01 to about 0.15. The polyoxymethylene polymer compositions provide polymer articles with improved tribological properties and mechanical properties.

To provide a polyacetal resin composition and a molded article thereof, which are less likely to crack even if stressed in contact with any hydrochloric acid-containing liquid. The polyacetal resin composition contains, per 100 parts by mass of a polyacetal resin: 0.01 to 10 parts by mass of at least one fatty acid metal salt selected from 1) to 3) below; and 0.1 to 5 parts by mass of a stress relaxant having a melting point of 67.5? C. to 200? C. when measured by using a differential scanning calorimeter at a flow rate of nitrogen of 20 cm.sup.3/min and at a heating rate of 10? C./min. 1) metal salt formed of long chain fatty acid having 10 to 34 carbon atoms and calcium; 2) metal salt formed of long chain fatty acid having 10 to 34 carbon atoms and zinc; and, 3) metal salt formed of long chain fatty acid having 10 to 34 carbon atoms and magnesium.

To provide a polyacetal resin composition and a molded article thereof, which are less likely to crack even if stressed in contact with any hydrochloric acid-containing liquid. The polyacetal resin composition contains, per 100 parts by mass of a polyacetal resin: 0.01 to 10 parts by mass of at least one fatty acid metal salt selected from 1) to 3) below; and 0.1 to 5 parts by mass of a stress relaxant having a melting point of 67.5? C. to 200? C. when measured by using a differential scanning calorimeter at a flow rate of nitrogen of 20 cm.sup.3/min and at a heating rate of 10? C./min. 1) metal salt formed of long chain fatty acid having 10 to 34 carbon atoms and calcium; 2) metal salt formed of long chain fatty acid having 10 to 34 carbon atoms and zinc; and, 3) metal salt formed of long chain fatty acid having 10 to 34 carbon atoms and magnesium.

Polyoxymethylene compositions, articles comprising these compositions, and processes of making the compositions, comprising: a) at least one polyoxymethylene polymer; b) about 0.1 to about 5 wt. % of poly alpha-1,3-glucan having a d90 particle size of 50 microns or less; c) optionally, at least one additive selected from the group consisting of nucleating agents, waxes, ultraviolet stabilizers, colorants, antioxidants, formaldehyde scavengers, lubricants, and mixtures of these; wherein an article molded from said polyoxymethylene composition exhibits a formaldehyde emission of 1 weight percent or less when measured according to TEF test method.

Polyoxymethylene compositions, articles comprising these compositions, and processes of making the compositions, comprising: a) at least one polyoxymethylene polymer; b) about 0.1 to about 5 wt. % of poly alpha-1,3-glucan having a d90 particle size of 50 microns or less; c) optionally, at least one additive selected from the group consisting of nucleating agents, waxes, ultraviolet stabilizers, colorants, antioxidants, formaldehyde scavengers, lubricants, and mixtures of these; wherein an article molded from said polyoxymethylene composition exhibits a formaldehyde emission of 1 weight percent or less when measured according to TEF test method.

Polyoxymethylene compositions, articles comprising these compositions, and processes of making the compositions, comprising: a) at least one polyoxymethylene polymer; b) about 0.1 to about 5 wt. % of poly alpha-1,3-glucan having a d90 particle size of 50 microns or less; c) optionally, at least one additive selected from the group consisting of nucleating agents, waxes, ultraviolet stabilizers, colorants, antioxidants, formaldehyde scavengers, lubricants, and mixtures of these; wherein an article molded from said polyoxymethylene composition exhibits a formaldehyde emission of 1 weight percent or less when measured according to TEF test method.

A polyacetal resin composition suitable for providing a plate-shaped resin molded article that satisfies all of the following: high flatness, low shrinkage ratio anisotropy (high dimensional stability), high creep resistance, high impact strength, and excellent color stability during residence in the molding machine. The polyacetal resin composition for molding a plate-shaped molded article includes 100 mass parts of a polyacetal resin having a melt index (according to ASTM D1238, 190 C., 2.16 kgf) of 2.0 g/10 min to 4.0 g/10 min; 0.1 mass parts to 2 mass parts of a polyacetal copolymer that is a copolymer of (b1) trioxane, (b2) a compound having two to four cyclic ether units per one molecule, and (b3) a compound having one cyclic ether unit per one molecule, the polyacetal copolymer having a branched or crosslinked structure; and 0.1 mass parts to 1 mass part of a hindered phenol antioxidant.

The purpose of the present invention is to provide: a polyacetal resin composition which is excellent in terms of impact resistance, thermal stability, and releasability; and a process for producing the polyacetal resin composition. The polyacetal resin composition comprises 100 parts by mass of a polyacetal resin (A) in which the molecular chain has neither a crosslink nor a branch therein, 0.01-10.0 parts by mass of an antioxidant (B), 0.01-5.0 parts by mass of a nitrogenous compound (C), and 0.05-1.0 parts by mass of a fatty acid amide (D), and has a melt index, as measured in accordance with ISO 1133, of 0.5-1.5 g/10 min. A process for producing the polyacetal resin compositions is also provided.